Biological molecules (e.g., proteins and nucleic acids) are widely present in any number of materials such as tissue and cells, and often need to be isolated from the material to facilitate downstream detection or use of the biological molecule. Nucleic acid, for instance, is typically isolated using silica-based fixed bed columns or silica magnetic particles. Such silica-based methods, however, exclude nucleic acids that are smaller than about 200 nucleotides in length, for example, microRNAs (miRNAs), which have a length of about 21 nucleotides to about 26 nucleotides.
Accordingly, silica-based methods are combined with acid phenol and chloroform extraction (in the presence of high molarity guanidine isocyanate) to isolate both larger and smaller RNA molecules (e.g., total RNA). Acid phenol and chloroform extraction thus adds additional time and expense to the isolation of miRNAs, in addition to necessitating proper disposal of the organic waste material.
Accordingly, a need exists for the identification and development of new methods for the isolation of nucleic acids, especially miRNAs, to facilitate downstream detection and use of these isolated nucleic acids.